Project Abstract Despite increased recognition that patients? social needs shape health trajectories and growing evidence that identifying and addressing these needs can impact health outcomes, little is known about how best to incorporate social needs screening and community referral programs into the practice of care delivery. A strong body of research in this area is needed to inform quality measure development, payment and incentive models, and other emerging policy initiatives that promote medical and social care integration as one part of a comprehensive strategy for improving health and decreasing health inequities. The necessary implementation research to inform these efforts is particularly challenging since comparative research in this field requires real world delivery settings that are investing in integrated care and where it is feasible to trial different strategies. The proposed study provides a unique opportunity to conduct comparative research by taking advantage of two existing, funded programs in community health centers serving low-income populations, which are most likely to benefit from the implementation of social screening and intervention programs. The two programs being leveraged for this comparative trial are the Oregon demonstration of the Center for Medicare and Medicaid Innovation?s Accountable Health Communities (AHC) and OCHIN?s Approaches to CHC Implementation of SDH Data Collection and Action (ASCEND) trial. The concurrent and overlapping initiatives provide an opportunity to conduct the first comparative study on social needs screening and intervention program implementation in this field. The four group natural study design proposed for the combined trial enables us to compare the relative effectiveness of ASCEND?s rich implementation supports with the Oregon AHC site?s financial incentives, as well as to compare each individual implementation strategy with the programs? combined effects and with non-intervention controls. The five-year, mixed methods proposal includes quantitative evaluation of the extent of screening and referrals during both active implementation and an 18 month maintenance phase, as well as a comparison of the program costs for each study arm. The study also involves qualitative data collection that will complement the quantitative analyses in order to help us understand contextual factors influencing the adoption, implementation, and maintenance of social programs and the impacts of these programs on staff, clinicians, and clinic workflow.